That sounds really rough! I have read that when this happens stopping them from hitting/biting/pulling and saying “Ow that hurts Mommy/gentle hands please” helps. If he is banging his head against the wall you can hold either your hand or a pillow in between his head and the wall to prevent him from hurting himself, maybe say “Mommy is protecting your head/I won’t let you hurt yourself” then offer empathy about what’s upsetting him and try to help him calm down. Toddlers and children need us to help name what they are feeling and share our calm when they are overwhelmed, and modeling ways that they can calm down by doing it in front of them or with them helps (deep breaths by saying “smell the roses/blow out the candle” while you hold up fingers for example)
My son is about to turn 16 months and he usually only does those things when he is sending me a message that he is unhappy but when he takes it out on me (biting,smacking) I stop him from doing so and then tell him owe that hurt mommy I’m sorry you’re upset and I pout/ act sad kind of like reminding him his actions have consequences.